DOGAMI to Collect Geophysical Data in Eastern Oregon
By Garrett Christensen on Monday, May 8th, 2023 in More Top Stories Northeastern Oregon News
BAKER CITY – (Release from DOGAMI) The Oregon Department of Geology and Mineral Industries (DOGAMI) has contracted NV5 and EDCON-PRJ to oversee Precision GeoSurveys for the collection, processing, and delivery of aeromagnetic and radiometric data in eastern Oregon. This airborne geophysical data is being collected to support future geologic mapping and geologic hazard analysis projects planned in the region.
When and where will these surveys be conducted?
The geophysical exploration surveys will be conducted in the Baker Valley, parts of the Harney Valley, and Dixie Butte in May and June, 2023. Baker Valley will be collected in mid-to-late May. Harney Valley and Dixie Butte will be collected in late May and June. Exact dates of collection will be provided as soon as ground conditions are right, and flights are officially scheduled.
The Oregon Department of Geology and Mineral Industries (DOGAMI) is an independent agency of the state of Oregon. DOGAMI develops maps, reports, earth science data, and other geographical information to help Oregonians understand the state’s unique geologic setting, geologic history, manage its natural resources, and prepare for natural hazards. Learn more about DOGAMI’s role in Oregon and explore geologic publications at the agency website, http://www.oregon.gov/dogami
What is aeromagnetic and radiometric data and how is it collected?
Aeromagnetic and radiometric surveys are the collection of geophysical data used to support detailed geologic studies of the Earth.
- An aeromagnetic survey is a kind of passive geophysical investigation that makes use of airborne surveying gauges installed in an aircraft (helicopter or airplane) at a certain flight height range to measure variations or anomalies in the Earth’s magnetic intensity over the target area. For helicopter surveys, a magnetometer on a forward mounted boom on the aircraft is used that samples 10 times a second. An onboard GPS system provides accurate positioning of the aircraft and sensor within 2 to 4 feet. The survey aircraft fly at a constant low altitude: 400 feet above ground for most areas and 500 feet above ground over Baker City to reduce aircraft noise. The primary east-west flight lines will be spaced 650 feet apart and north-south trending tie lines will be flown at 1.2-mile spacing. Airborne surveying will be accompanied by a series of base station magnetometers monitoring the collection. These huge volumes of magnetic measurements will be processed into a digital aeromagnetic map.
- Radiometric data collection is another passive geophysical process used to estimate concentrations of the radioactive elements potassium, uranium, and thorium present in the upper part of the Earth’s crust. Airborne radiometric surveys estimate the concentrations of the radioelements at the Earth’s surface by measuring the natural gamma radiation emitted by these elements from low-flying aircraft or helicopters. Radiometric data acquisition is completed simultaneously with aeromagnetic survey acquisition.
How will DOGAMI use this data?
Airborne geophysical data is essential information needed to produce new high-resolution geologic maps, better understand geologic hazards such as earthquakes, and inventory and manage natural resources, such as groundwater and critical minerals. Baker Valley, Harney Valley, and Dixie Butte are key focus areas for DOGAMI to conduct geologic mapping due to the importance of conservation and sustainability of water resources and the strategic need to identify critical minerals necessary for modern technologies, economies, and national security.
Will these surveys cause any disturbances on the ground, and will any additional information over the target areas be collected during data acquisition?
- No. All sensors used in the collection of data for these surveys are passive recording devices and emit no energy or signals, aside from an altimeter that uses an eye-safe infrared laser to monitor flying height above the ground.
- No photographic or video images will be collected during survey operations.
